ABSTRACT
Thedevelopmentoftheoriesofinterestforastationaryeconomy,which wetracedintheprecedingchapters,offersagoodexampleoftheevolutionofscientificthought.Bohm-Bawerkhadbasedhistheoryongreatly simplifiedpremises:theonlyproductivefactorcontainedinhisanalysis waslabour;heassumedan"evenflow"processofproductioninwhich onlyoneproductwasproducedandonlycirculatingcapitalexisted;he workedwithsimpleinterest.Wicksellelaboratedthistheorybyintroducingmorethanonefactorofproductionandmorethanoneproduct, andbyapplyingageneralequilibriumanalysisoftheWalrasiantype,improving,however,uponWalrasbytakingthetimeelementintoaccount.In hislatercontributions,Wicksellsubstitutedcompoundinterestforsimple interestandalsoexaminedthecaseofproductiveinputswhoseinvestment periodscouldbevariedindividually.Buthe,too,retainedtheassumptionthatonlycirculatingcapitalexisted.Akermantookthenextstepby formulatinghistheoryentirelyforthecaseoflong-liveddurablegoods. Hayek,finally,undertookacompleteclassificationofthevarioustypes ofinvestmentsandinvestigatedthese-atleastforthecaseofastationary economy-without,however,arrivingataclear-cutsolutiontotheproblemoftheleveloftheinterestrate.Thusthegroupoftheoriesdiscussed inthispartofthebookhasatleastthemeritofhavingdefinedthewhole rangeofinvestmentpossibilitieswhichacompletetheorywouldneedto cover.Atthesametime,thedevelopmentofthetheorydemonstratedthat certainconceptsandideaswereuntenableandhadtobeabandoned.This finallyledtotherealizationthataninteresttheoryforastationaryeconomy,suchastheauthorsofthisgroup-withtheexceptionofHayekhadbeenstrivingtoformulate,wasimpossibletoconstructalongthe linestheyhadattemptedtofollow.
